This invention relates, in general, to surgery of the eye, and more particularly to a self-sealing episcleral incision useful in scleral tunnel surgery for the removal of cataracts and the implantation of artificial lenses.
It is well known to those in the opthalmology arts that microsurgery may be used to remove cataracts and implant artificial lenses to partially or wholly restore vision. Initially, a conjunctival incision is made to partially remove the conjunctiva and expose the limbus and sclera. The most conventional microscopic surgery method currently employed includes making an incision in either the limbus or the sclera directly posterior to the limbus. The incision is either linear or approximately follows the curvature of the limbus and extends into the anterior chamber directly in front of the iris.
A capsulrhexis is performed wherein a window is cut into the anterior of the crystalline lens capsule. Once the crystalline lens is opened, phacoemulsification is performed wherein the nucleus is removed using ultrasonic frequency and aspiration. The cortex is then removed by aspiration only. Once the nucleus and cortex have been removed, the empty lens capsule remains.
Following removal of lens material which includes the cataract, an artificial lens is implanted. The artificial lens is inserted through the incision, disposed in the empty lens capsule and stabilized therein. The artificial lens implant may be either a solid implant or a flexible folded implant. Both these types of implants are well known in the art. Once the lens implant has been successfully inserted into the lens capsule and stabilized, the incision is sealed with sutures so that the eye may be inflated.
A common problem with the described conventional microsurgery is suture induced astigmatism. The cornea is a potentially toric structure. The use of sutures in the limbus to seal the incision maximally alters the toricity of the cornea often creating an astigmatism which impairs vision. Additional suture induced complications include irritation of the eye, suture absesses, suture extrusion and foreign body reaction. Further, the fine sutures employed in opthalmic surgery are subject to breakage thereby exposing the wound to separation and dehiscence.
Scleral tunnel surgery greatly reduces the effect of sutures and suture induced astigmatism because the sutures are not disposed in the limbus, are much further away from the cornea and any material gathered by the sutures is sclera and not cornea. Standard scleral tunnel surgery includes making an incision in the sclera approximately 1 to 2 millimeters posterior to the limbus. This incision is also linear or approximately follows the curvature of the limbus. Following the scleral incision, a pocket or tunnel is formed through the sclera that extends into the anterior chamber of the eye.
Capsulrhexis, phacoemulsification and removal of the cortex to leave the empty lens capsule are performed in the same manner as described above. The artificial lens implant is inserted through the episcleral incision, transits the scleral tunnel and is properly positioned and stabilized in the empty lens capsule. The episcleral incision is then sealed with sutures and the eye inflated. Although the sutures sealing the scleral incision are not as detrimental as sutures disposed in the limbus, it is still possible for them to detrimentally effect the toricity of the cornea and cause an astigmatism.
In view of the above, it would be highly beneficial to have an episcleral incision that may be employed with scleral tunnel microsurgery that is substantially self-sealing, will admit solid or folded lens implants and greatly reduces or eliminates the probability of astigmatism.